The prior art discloses various solutions with a sensor for measuring a physical quantity, such as for example a heart rate band or belt. The heart rate band is made of skin contacting electrodes, and electronics which identifies a signal emanating from the electrodes and transmits the received heart rate data to a terminal, for example to a watch or a mobile communicator. For conducting a measurement, the heart rate band is put on for example around the thorax, whereby the electrodes make contact with the skin around the chest close to the heart for a measuring process.
For example, publication FI 119456 discloses one heart rate belt with a sensor, wherein the heart rate belt has its sensor in a first part of a connector mechanism and has its processing or transmitter unit in a second part of the connector mechanism. Both parts include magnetic layers, by means of which the parts connect releasably to each other by way of mechanical coupling. In the solution, the electrical conductor layers extending from the sensor are connected electrically with the second part electrical components of the processing or transmitter unit as a result of the aforesaid mechanical coupling.
In addition, publication FI 119716 discloses a heart rate measuring arrangement comprising a band-like structural component, wherein the structural component, in terms of its material, is flexible, soft, and closely fitting to the skin surface, such as for example a band-aid type adhesive tape. The arrangement includes an electronic unit in electrical communication with heart rate measuring electrodes. The unit is arranged in a casing which comprises a gripping means for attaching the unit to the band-like component of the electrode structure, such that the gripping means provide an electrical connection between the electrodes and the electronic unit. The gripping means is for example an attachment slot, a pivoted clamping clip or the like.
The prior art measuring arrangements are typically all plastic or rubber in structure, wherein for example the measuring band is fabricated with injection molding technology by pressing the conducting plastic electrodes, plastic insulations and electronics within the structure.
The prior art solutions nevertheless involve certain problems. Plastic bands are cold, among other things, and the hard and cold presence thereof does not feel comfortable on the skin. Therefore, recent newcomers to the marketplace include also heart rate measuring bands made partially of textile. On the other hand, a problem with partially textile bands is that the manufacturing processes of textile and those of plastics as well as those of electronics are clearly different from each other in terms of character and technology, which is why the textile sensor band, and electrodes integrated therewith, must be manufactured in a separate process and, respectively, the transmitter module must be manufactured in a separate process. A particular problem here is due to the fact that, in order to achieve a final product or, in other words, in order to bond a textile band and electronics to each other, it is absolutely necessary to provide therebetween a mechanically and electrically reliable connection, by which connection an electrical measurement signal can be delivered from the skin and sensors to the electronics. Since the measurement signal is highly sensitive to interferences and the environment is particularly demanding (sweaty and with motion disturbances), the connection is subject to quite high qualifications. In addition to communicating the signal, the connection is required, among other things, to retain the transmitter module mechanically immobile in attachment with a textile band. Coming up with sufficiently reliable bonding technique between a textile band and electronics is nevertheless quite expensive considering the final product.
It is a rough estimate that the price of a plastic heart rate band, having electronics integrated as a part of the plastic band, is only about 60% of that of a separate textile band and a transmitter attached thereto with prior art technology. The most significant cost factor is the necessary bonding technology between a textile band and a plastic transmitter. In most commercial solutions, the bonding technique between a band and a transmitter is typically implemented with snap fasteners.